Mesophilic anaerobic digestion of a mixture of cheese whey and diary manure

Abstract Mesophilic anaerobic digestion of a mixture of cheese whey and dairy manure was investigated using an anaerobic rotating biological contact reactor operated over a range of hydraulic retention time at various organic loading rates. Dairy manure provided nutrients and acted as a buffer to the cheese whey. Rates of production of methane from the mixture were between those of cheese whey and screened dairy manure and in agreement with calculated theoretical methane production rates. Methane production rate showed a linear relationship with the organic loading rate. The highest methane production rate was 3·74 litre methane litre−1 day−1. Reduction in the chemical oxygen demand ranged from 46·3% to 67·5%. Anaerobic digestion of such mixtures could be used as an initial waste treatment for cheese whey.